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Low-dimensional model of turbulent mixed convection in a complex domain

Bailon-Cuba, Jorge und Shishkina, Olga und Wagner, Claus und Schumacher, Joerg (2012) Low-dimensional model of turbulent mixed convection in a complex domain. Physics of Fluids, Vol. 2 (10), Seiten 1-20. American Institute of Physics (AIP). DOI: 10.1063/1.4757228. ISSN 1070-6631.

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Offizielle URL: http://dx.doi.org/10.1063/1.4757228

Kurzfassung

We construct a low-dimensional model (LDM) of turbulent mixed convection in a Cartesian cell with in- and outlets and local sources of heat which is narrow in one of the two horizontal space directions. The basis is a high-resolution three-dimensional direct numerical simulation (DNS) record. The model is derived with basis functions, which have been obtained by a proper orthogonal decomposition (POD) using the snapshot method. The POD analysis is applied for a sequence of three-dimensional snapshots aswell as for datawhich are bulk-averaged in the direction of narrowextension. This step is taken since the flow is found to have no significant dependence along this direction in the cell. We compare the three-dimensional and two-dimensional POD modes. This simplification reduces the complexity of the problem significantly and allows us to construct and run a two-dimensional LDM with a small number of degrees of freedom. We study the long-time dynamical behavior of this system using a closure of the LDM based on a mode-dependent viscosity and diffusivity. The LDM has been optimized in terms of the standard deviation of the energy spectrum and the transient energy for different numbers of degrees of freedom by comparison with the original DNS data. We find that the evolution of the coherent structures of flow and temperature agrees well with the two-dimensional original data and determine their contribution to the global transfer of heat. Root-mean-square profiles of the fluctuations of the turbulent fields agree qualitatively well with the original simulation data, but deviate slightly in amplitude. We conclude that the reduction in the dimensionality and the number of degrees of freedom can reproduce the gross features of the mixed convection flow in this particular setup well.

Dokumentart:Zeitschriftenbeitrag
Zusätzliche Informationen:ISSN Online: 1089-7666
Titel:Low-dimensional model of turbulent mixed convection in a complex domain
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Bailon-Cuba, Jorgejorge.bailon-cuba@tu-ilmenau.de
Shishkina, OlgaOlga.Shishkina@dlr.de
Wagner, Clausclaus.wagner@dlr.de
Schumacher, JoergJoerg.Schumacher@tu-ilmenau.de
Datum:2012
Erschienen in:Physics of Fluids
Referierte Publikation:Ja
In Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:Vol. 2
DOI :10.1063/1.4757228
Seitenbereich:Seiten 1-20
Verlag:American Institute of Physics (AIP)
ISSN:1070-6631
Status:veröffentlicht
Stichwörter:mixed convection, Direct numerical simulations, proper orthogonal decomposition, low-dimensional model
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Verkehr
HGF - Programmthema:Bodengebundener Verkehr
DLR - Schwerpunkt:Verkehr
DLR - Forschungsgebiet:V BF - Bodengebundene Fahrzeuge
DLR - Teilgebiet (Projekt, Vorhaben):V - Next Generation Train (alt)
Standort: Göttingen
Institute & Einrichtungen:Institut für Aerodynamik und Strömungstechnik > Fluidsysteme
Hinterlegt von: PD Dr. habil. Olga Shishkina
Hinterlegt am:12 Nov 2012 15:17
Letzte Änderung:12 Dez 2013 21:49

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